A flange part is formed in a shape whose diameter increases toward an outer diameter side of a center core. The flange part closes a space between an end of a magnetic delivery core on a second side in the axial direction and an end of the center core on the second side in the axial direction. An output member includes a contact part, which is brought into contact with an end of the center core on a first side in the axial direction when a plunger moves toward the second side in the axial direction. When the contact part is brought into contact with the end of the center core on the first side in the axial direction, the plunger defines an axial clearance between the plunger and the flange part.